Pair your compatible Garmin unit with the HRM-Run to get not only heart rate information but also real-time feedback about your running form
HRM-Run has an accelerometer in the module that measures torso movement in order to calculate 3 different running metrics

Cadence : The number of steps per minute. It displays the total steps (right and left combined)

Vertical oscillation : The bounce in your running motion. It displays the vertical motion of your torso, measured in centimeters

Ground Contact Time : The amount of time in each step that you spend on the ground while running. It is measured in milliseconds